BITS 64 decode: xor dword [rel next], 0x12345678 xor word [rel next], 0x5678 xor byte [rel next], 0x78 ; repeat as many times as needed next: db 0x41, 0x42, 0x43, 0x44 encode: xor dword [rel next], 0x12345678 ; partial encoded that fixes badcharacters by encoding at offsets ; where there are bad characters